Distribution of local deformations in diamond crystals according to the analysis of Kikuchi lines profile intensities

2013 ◽  
Vol 35 (4) ◽  
pp. 220-226 ◽  
Author(s):  
M. D. Borcha ◽  
S. V. Balovsyak ◽  
I. M. Fodchuk ◽  
V. Yu. Khomenko ◽  
V. N. Tkach
Keyword(s):  
Diamond Crystals ◽  
Kikuchi Lines ◽  
Local Deformations

Domain Formation in Synthetic Quartz

1971 ◽  
Vol 29 ◽  
pp. 156-157
Author(s):  
Joseph J. Comer
Keyword(s):  
Electron Beam ◽  
Room Temperature ◽  
Domain Formation ◽  
Synthetic Quartz ◽  
Transmission Electron ◽  
Black Spots ◽  
Diffraction Mode ◽  
Domain Boundaries ◽  
Kikuchi Lines ◽  
Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

Effects of High-Energy Ions on Synthetic Quartz

1972 ◽  
Vol 30 ◽  
pp. 544-545
Author(s):  
Joseph J. Comer ◽  
Charles Bergeron ◽  
Lester F. Lowe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
High Energy ◽  
Transmission Electron ◽  
Kikuchi Lines ◽  
High Energy Ions ◽  
Diffraction Patterns ◽  
Dauphiné Twinning ◽  
Beam Damage

Using a Van De Graaff Accelerator thinned specimens were subjected to bombardment by 3 MeV N+ ions to fluences ranging from 4x1013 to 2x1016 ions/cm2. They were then examined by transmission electron microscopy and reflection electron diffraction using a 100 KV electron beam.At the lowest fluence of 4x1013 ions/cm2 diffraction patterns of the specimens contained Kikuchi lines which appeared somewhat broader and more diffuse than those obtained on unirradiated material. No damage could be detected by transmission electron microscopy in unannealed specimens. However, Dauphiné twinning was particularly pronounced after heating to 665°C for one hour and cooling to room temperature. The twins, seen in Fig. 1, were often less than .25 μm in size, smaller than those formed in unirradiated material and present in greater number. The results are in agreement with earlier observations on the effect of electron beam damage on Dauphiné twinning.

High-Resolution Image Simulation of a Tilted Crystal

1990 ◽  
Vol 48 (1) ◽  
pp. 68-69
Author(s):  
C. J. D. Hetherington
Keyword(s):  
High Resolution ◽  
Crystal Thickness ◽  
Thin Specimen ◽  
Atomic Structures ◽  
Kikuchi Lines ◽  
High Resolution Images ◽  
Final Estimate ◽  
Simulated Images ◽  
Habit Planes

Most high resolution images are not directly interpretable but must be compared with simulations based on model atomic structures and appropriate imaging conditions. Typically, the only parameters that are adjusted, in addition to the structure models, are crystal thickness and microscope defocus. Small tilts of the crystal away from the exact zone axis have only rarely been considered. It is shown here that, in the analysis of an image of a silicon twin intersection, the crystal tilt could be accurately estimated and satisfactorily included in the simulations.The micrograph shown in figure 1 was taken as part of an HREM study of indentation-induced hexagonal silicon. In this instance, the intersection of two twins on different habit planes has driven the silicon into hexagonal stacking. However, in order to confirm this observation, and in order to investigate other defects in the region, it has been necessary to simulate the image taking into account the very apparent crystal tilt. The inability to orientate the specimen at the exact [110] zone was influenced by i) the buckling of the specimen caused by strains at twin intersections, ii) the absence of Kikuchi lines or a clearly visible Laue circle in the diffraction pattern of the thin specimen and iii) the avoidance of radiation damage (which had marked effects on images taken a few minutes later following attempts to realign the crystal.) The direction of the crystal tilt was estimated by observing which of the {111} planes remained close to edge-on to the beam and hence strongly imaged. Further refinement of the direction and magnitude of the tilt was done by comparing simulated images to experimental images in a through-focal series. The presence of three different orientations of the silicon lattice aided the unambiguous determination of the tilt. The final estimate of a 0.8° tilt in the 200Å thick specimen gives atomic columns a projected width of about 3Å.

Effect of pressure on synthetic diamond crystals at high temperatures and pressures in Fe/Ni catalyst system

CrystEngComm ◽  
2021 ◽  
Author(s):  
Shuai Fang ◽  
Yongkui Wang ◽  
Liangchao Chen ◽  
Zhiyun Lu ◽  
Zhenghao Cai ◽  
...  
Keyword(s):  
Nitrogen Content ◽  
Growth Mechanism ◽  
Synthetic Diamond ◽  
Natural Diamond ◽  
Catalyst System ◽  
Necessary Condition ◽  
Ni Catalyst ◽  
Effect Of Pressure ◽  
Diamond Crystals ◽  
System P

Pressure is a necessary condition for the growth of natural diamond. Studying the effect of pressure on the nitrogen content of diamond is important for exploring the growth mechanism of...

Generation of laser radiation by color centers in diamond crystals (review)

2021 ◽  
Author(s):  
V. P. Mironov ◽  
E. A. Protasova ◽  
E. I. Lipatov ◽  
E. F. Martynovich
Keyword(s):  
Laser Radiation ◽  
Color Centers ◽  
Diamond Crystals

Characterization of diamond thin films: Diamond phase identification, surface morphology, and defect structures

1989 ◽  
Vol 4 (2) ◽  
pp. 373-384 ◽  
Author(s):  
B. E. Williams ◽  
J. T. Glass
Keyword(s):  
Electron Microscopy ◽  
Surface Morphology ◽  
Methane Concentration ◽  
Microwave Plasma ◽  
Defect Density ◽  
Diamond Films ◽  
Hydrogen Gas ◽  
Phase Identification ◽  
Diamond Crystals ◽  
Thin Carbon

Thin carbon films grown from a low pressure methane-hydrogen gas mixture by microwave plasma enhanced CVD have been examined by Auger electron spectroscopy, secondary ion mass spectrometry, electron and x-ray diffraction, electron energy loss spectroscopy, and electron microscopy. They were determined to be similar to natural diamond in terms of composition, structure, and bonding. The surface morphology of the diamond films was a function of position on the sample surface and the methane concentration in the feedgas. Well-faceted diamond crystals were observed near the center of the sample whereas a less faceted, cauliflower texture was observed near the edge of the sample, presumably due to variations in temperature across the surface of the sample. Regarding methane concentration effects, threefold {111} faceted diamond crystals were predominant on a film grown at 0.3% CH4 in H2 while fourfold {100} facets were observed on films grown in 1.0% and 2.0% CH4 in H2. Transmission electron microscopy of the diamond films has shown that the majority of diamond crystals have a very high defect density comprised of {111} twins, {111} stacking faults, and dislocations. In addition, cross-sectional TEM has revealed a 50 Å epitaxial layer of β3–SiC at the diamond-silicon interface of a film grown with 0.3% CH4 in H2 while no such layer was observed on a diamond film grown in 2.0% CH4 in H2.

Growth mechanism of icosahedral and other five-fold symmetric diamond crystals

2015 ◽  
Vol 25 (5) ◽  
pp. 1587-1598 ◽  
Author(s):  
Qiu-ping WEI ◽  
Li MA ◽  
Jun YE ◽  
Zhi-ming YU
Keyword(s):  
Growth Mechanism ◽  
Diamond Crystals
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